Update '.drone.yml'

.drone.yml

@@ -33,7 +33,7 @@ steps:
   - name: deploy to staging
     commands:
       - cd /apps/willaengine-staging/ ; docker-compose up -d
-      - docker exec willaengine bash -c "COMPOSER=composer-staging.json composer update"
+      - docker exec willaengine-staging_php bash -c "COMPOSER=composer-staging.json composer update"
       # - docker exec willaengine-staging_php service supervisor start
       # - docker exec willaengine-staging_php php artisan migrate --path=vendor/wm/finance/database/migrations
     when: